Iraqi Kurds held an election today that most of the world did not want to happen. It's a referendum on Kurdish independence from Iraq. Voters are expected to support it strongly. If that happens, the U.S. says, it could divide Iraq as it's fighting ISIS. And neighboring Turkey, Iran and Syria worry Kurds within their borders will also seek independence.

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Complicating matters further, the Kurds didn't just hold a vote in the semi-autonomous region they control. They also held it in disputed areas where Arabs and other ethnic and religious groups also live. NPR's Jane Arraf reports from one of those places, Kirkuk.

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JANE ARRAF, BYLINE: Voting in this Kurdish neighborhood of Kirkuk was a bit like a street party. Outside the school turned into a polling station, there was a horn player and drummer, and inside a stream of Kurdish families coming to check the box for yes on a ballot that asked, do you want the Kurdistan region and the disputed territories to be an independent country? Iman and Shama Ayoub - sisters and high school students - were wearing glittery traditional Kurdish gowns. Shama wore a headband of silver coins.

SHAMA AYOUB: (Foreign language spoken).

ARRAF: She says independence would open the door to opportunities for work and travel. Parents brought their children to vote, letting them stand on tiptoe to put the ballots in the boxes. Kirkuk has been controlled by Kurdish forces for the last three years. They moved it to secure the city and the oil fields when the Iraqi army collapsed in the face of ISIS. But there's also a substantial Arab and Turkmen population here. Most of them have boycotted this referendum. I went to one Arab-Turkmen area to see what was happening there.

Almost all the shops are closed in this Arab-Turkmen neighborhood, even the ones that would normally be open on a holiday, like the bakeries and the clothing stores. A couple of people said people are staying at home today because they're afraid.

RAYHANA SADEQ: (Through interpreter) We've been in this neighborhood for 30 years. Our neighbors are Turkmen and Arab. They've never done anything bad to us. It's the Arab government that's bad.

ARRAF: At this polling station, that's Rayhana Sadeq. She's Kurdish. Most Arabs and Turkmen are worried about this vote, that it will rock the boat in a city that's always had a delicate balance. Some are afraid of clashes between Kurdish forces and Shia-Arab paramilitary forces under the control of the Baghdad government.

Eighty-three-year-old Omar Rasul Ahmed walked in slowly, leaning on a cane to cast his ballot. More than half a century ago, Ahmed fought the Iraqi army in the mountains with the legendary Kurdish leader Mullah Mustafa Barzani. Two decades later, Iraqi forces killed more than 100,000 Kurds and destroyed thousands of villages.

OMAR RASUL AHMED: (Foreign language spoken).

ARRAF: "All our sacrifices and all our martyrs have been for this day," he says.

Kurdish leaders will use the vote as a mandate to try to negotiate independence with Baghdad. That's what worries the U.S. and Iraq's neighbors. They opposed holding the referendum because it could lead to the breakup of Iraq and inspire Kurdish minorities in Turkey, Iran and Syria to try to follow their example. But Hawre Assi Saleh, an election worker, says he believes that countries that oppose Kurdish independence now will come around.